1. Field
The present disclosure relates to a pressure gas container and a vehicle including the pressure gas container.
2. Description of the Related Art
FIG. 11 is a longitudinal sectional view of the structure of a related-art high-pressure gas tank.
A high-pressure gas tank 101 for containing a high-pressure gas such as hydrogen includes, for example, a liner 102 and a reinforcing layer 103. The tank-shaped liner 102, which is a part where a high-pressure gas is contained, is formed of resin. The reinforcing layer 103 is formed of, for example, a carbon-fiber-reinforced plastic (CFRP) and covers the liner 102 so as to reinforce the liner 102. Here, the liner 102 provides gas barrier properties for the high-pressure gas tank 101 and the reinforcing layer 103 provides pressure resistance for the high-pressure gas tank 101.
A flange-shaped metal boss 104 having an insertion hole 104a at its center is provided in the high-pressure gas tank 101. A plug 105 is inserted into the insertion hole 104a of the metal boss 104 so as to close the insertion hole 104a. 
In the high-pressure gas tank 101, which is used in a fuel-cell vehicle or the like, a high-pressure fuel gas permeates through the resin liner 102. Thus, when the pressure inside the liner 102 of the high-pressure gas tank 101 is reduced, a pressure difference occurs between the pressure inside the resin liner 102 and the pressure of the high-pressure fuel gas accumulated in a gap between the liner 102 and the reinforcing layer 103.
Because of this pressure difference, the high-pressure fuel that accumulates in the gap between the liner 102 and the reinforcing layer 103 presses the liner 102, thereby causing deformation of the liner 102 such as buckling 102h as illustrated in FIG. 12.
In order to prevent the buckling 102h from occurring, a certain residual pressure needs to be maintained inside the liner 102. Thus, in the high-pressure gas tank 101, the effective amount of the fuel gas (the effective amount of hydrogen) that can be used is reduced.
Furthermore, during the maintenance of the high-pressure gas tank 101, the pressure in the high-pressure gas tank 101, that is, the pressure inside the liner 102, needs to be reduced to the atmospheric pressure. In this case, the occurrence of the buckling 102h of the liner 102 may be unavoidable.
In addition, when discarding the high-pressure gas tank 101, it is desirable that there be no accumulation of the gas in the gap between the liner 102 and the reinforcing layer 103.
Thus, technologies for addressing the above-described problem are disclosed in Japanese Unexamined Patent Application Publications No. 2009-216133, No. 2009-257355, and No. 2011-231900 as follows.
Japanese Unexamined Patent Application Publication No. 2009-216133 describes a structure, in which a plurality of vent holes that extend to an outer space are provided in the reinforcing layer 103, thereby dispersing the gas that accumulates in the gap between the liner 102 and the reinforcing layer 103. See, for example, FIG. 2 of Japanese Unexamined Patent Application Publication No. 2009-216133.
Japanese Unexamined Patent Application Publication No. 2009-257355 describes a structure, in which the liner 102 has grooves formed in the outer surface thereof so as to facilitate dispersion of the gas, thereby preventing the gas from accumulating in the gap between the liner 102 and the reinforcing layer 103. See, for example, FIGS. 1A, 1B, 2A, 2B, and 5 of Japanese Unexamined Patent Application Publication No. 2009-257355.
Japanese Unexamined Patent Application Publication No. 2011-231900 describes a structure, in which a gas dispersion facilitating layer, which is an intermediate layer including fine balls formed on the liner 102, is provided between the liner 102 and the reinforcing layer 103 so as to prevent the gas from accumulating. See, for example, FIG. 4 of Japanese Unexamined Patent Application Publication No. 2011-231900.